Measurements of branching fractions for electromagnetic transitions involving the χbJ (1P) states
Physical Review D - Particles, Fields, Gravitation and Cosmology 83:5 (2011)
Abstract:
Using (9.32, 5.88) million Υ(2S,3S) decays taken with the CLEO III detector, we obtain five product branching fractions for the exclusive processes Υ(2S)→γχb0,1,2(1P)→γγΥ(1S) and Υ(3S)→γχb1,2(1P) →γγΥ(1S). We observe the transition χb0(1P) →γΥ(1S) for the first time. Using the known branching fractions for B[Υ(2S)→γχbJ(1P)], we extract values for B[χbJ(1P)→γΥ(1S)] for J=0, 1, 2. In turn, these values can be used to unfold the Υ(3S) product branching fractions to obtain values for B[Υ(3S)→γχb1,2(1P)] for the first time individually. Comparison of these with each other and with the branching fraction B[Υ(3S)→γχb0] previously measured by CLEO provides tests of relativistic corrections to electric dipole matrix elements. © 2011 American Physical Society.Measurement of J/psi production in pp collisions at sqrt(s)=7 TeV
(2011)
Brief Reports γ(1 S) →γf2′(1525); F2′(1525)→ KS0KS0, decays.
Physical Review D Particles Fields Gravitation and Cosmology 83:3 (2011)
Abstract:
We report on a study of exclusive radiative decays of the Υ(1S) resonance into a final state consisting of a photon and two KS0 candidates. We find evidence for a signal for Υ(1S)→γf2′(1525); f2′(1525)→γKS0KS0, at a rate B(Υ(1S) →γf2′(1525))=(4.0±1.3±0.6)×10-5, consistent with previous observations of Υ(1S)→γf2′(1525) ; f2′(1525)→K+K-, and isospin. Combining this branching fraction with existing branching fraction measurements of Υ(1S)→γf2′(1525) and J/ψ→γf2′(1525), we obtain the ratio of branching fractions: B(Υ(1S) →γf2′(1525))/B(J/ψ→γf2′(1525))=0. 09±0.02, approximately consistent with expectations based on soft-collinear effective theory. © 2011 American Physical Society.Measurement of the B- lifetime using a simulation free approach for trigger bias correction
Physical Review D Particles Fields Gravitation and Cosmology 83:3 (2011)
Abstract:
The collection of a large number of B-hadron decays to hadronic final states at the CDF II Detector is possible due to the presence of a trigger that selects events based on track impact parameters. However, the nature of the selection requirements of the trigger introduces a large bias in the observed proper-decay-time distribution. A lifetime measurement must correct for this bias, and the conventional approach has been to use a Monte Carlo simulation. The leading sources of systematic uncertainty in the conventional approach are due to differences between the data and the Monte Carlo simulation. In this paper, we present an analytic method for bias correction without using simulation, thereby removing any uncertainty due to the differences between data and simulation. This method is presented in the form of a measurement of the lifetime of the B- using the mode B-→D0π -. The B- lifetime is measured as τB -=1.663±0.023±0.015ps, where the first uncertainty is statistical and the second systematic. This new method results in a smaller systematic uncertainty in comparison to methods that use simulation to correct for the trigger bias. © 2011 American Physical Society.First observation of Bs -> J/psi f0(980) decays
(2011)